Re: What do Cokes or other carbonated sodas do to your stomach?

It is true that soft drinks are very acidic (the pH of most carbonated 
beverages is about 3.0) (Potter and Hotchkiss, Food Science, 5th edition). 
The pH of the food that leaves the stomach is about 2.0, so the soft drinks 
are less acidic than stomach contents.  This means that the soft drink 
would be further acidified in the stomach.  The stomach has a remarkable 
capacity to adapt to a variety of foods with few side effects.  In most 
people, the acidity of the food eaten has very little effect on the 
stomach.  Soft drinks also are fairly high in sugar, with a sugar 
concentration of about 12% (Potter and Htochkiss, Food Science, 5th ed.) 
and many also contain caffeine.  If you only infrequently consume foods 
that are high in sugar or that contain caffeine, the symptoms you note may 
be related to them rather than to any effect on your stomach.  A rapid 
increase in blood sugar may make a person feel somewhat "unsettled" for a 
few minutes.  Similarly, caffeine may do the same in a person who is not 
accustomed to consuming it.  There is no indication that consumption of 
soft drinks has any short-term or long-term harmful effect on the stomach 
in healthy people.  If there were, the FDA would be obligated to remove the 
products from the market.